Mark forming record materials

ABSTRACT

A CHROMOGENIC MATERIAL OF NORMALLY COLORLESS FORM IS DISCLOSED, HAVING A STRUCTURAL FORMULA:   3-(O=),6&#39;&#39;-((R3)2-N-),2&#39;&#39;-R1,3&#39;&#39;-R,R2-SPIRO(PHTHALAN-1,9&#39;&#39;-   XANTHENE)   WHEREIN ONE OF R1 AND R2 REPRESENTS A CHEMICAL RADICAL HAVING THE STRUCTURE   2-(R5-N-),3-Y-NAPHTHALENE   OR A CHEMICAL RADICAL HAVING THE STRUCTURE   1-(R5-N-),2-Y,4-Z-BENZENE   WHEREIN R5 REPRESENTS AN ALKYL RADICAL HAVING LESS THAN FIVE CARBON ATOMS OR HYDROGEN RADICALS, Z REPRESENTS NITRO-,AMINO DIALKYLAMINO-, ALKYL RADICALS HAVE LESS THAN FIVE CARBON ATOMS, OR HYDROGEN RADICALS, AND Y COMPRISES NITRO-, AMINO-, CARBOXYL, HYDROGEN AND ESTER RADICALS AND THE REMAINING OTHER R1 AND R2 COMPRISES AMINO-, NITRO-, HYDROGEN, ALKYL HAVING LESS THAN FIVE CARBON ATOMS ACETAMIDO ND HALOGEN RADICALS; R COMPRISES HYDROGEN RADICALS AND ALKYL RADICALS HAVING LESS THAN FIVE CARBON ATOMS; AND R3 COMPRISES ALKYL RADICALS HAVING LESS THAN FIVE CARBON ATOMS-SAID MATERIAL ASSUMING A COLORED FORM UPON REACTIVE CONTACT WITH A LEWIS ACID MOLECULE. EXAMPLES INCLUDE 2&#39;&#39;-(2-CARBOXYANILINO)-6&#39;&#39;-DIETHYLAMINOFLUORAN; 2&#39;&#39;-(ANILINO-6&#39;&#39;-DIETHYLAMINOFLUORAN; 2&#39;&#39;-(3-CARBOMETHOXY -2-NAPATHYLAMINO)-6&#39;&#39;-DIETHYLAMINOFLUORAN; 2&#39;&#39;(2-CARBOMETHOXYANILINO)-6&#39;&#39;DIETHYLAMINO-3&#39;&#39;-METHYLFLUORAN; 2&#39;&#39;-(3-CARBOXY-2-NAPHTHYLAMINO)-6&#39;&#39;-DIETHYLAMINO-3&#39;&#39;METHYLFLUORORAN; 6-(2-CARBOXYANILINO)-2&#39;&#39;-CHLORO-6&#39;&#39;-DIETHYLANINO-3&#39;&#39;METHYLFLUORAN; 2&#39;&#39;-(2-CARBOXY-4-NITROANILINO)-6&#39;&#39;-DIETHYLAMINOFLUORAN; 6&#39;&#39;-DIETHYLAMINO-2&#39;&#39;-(N-METHYLANILINO)FLUORAN; AND 6&#39;&#39;-DIETHYLAMINO-2&#39;&#39;-(2,4-DINITROANILINO)FLUROAN.

y 17, 1973 CHAO-HAN LIN 3,745,562

MARK-FORMING RECORD MATERI LS Original Filed Nov. 16, 1970 BASE-SHEET OFRECORD MATERIAL COATED ON THE REAR WITH MINUTE A PRESSURE-RUPTURABLECAPSULES CONTAINING LIQUID SOLUTION 0F CHROMOGENIC MATERIAL DEVELOPABLE'ON CONTACT WITH AN ELECTRON- ACCEPTING MATERIAL OF THE LEWIS- ACID TYPETo coLoREo FORM RECEIVING SURFACE OF UNDERSHEET COATED WITH ANELECTRON-ACCEPTING MATERIAL OF THE LEWIS- ACID TYPE FIG. 2

United States Patent Int. Cl. B41m /22; C07d 5/34 US. Cl. 117-36.2 15Claims ABSTRACT OF THE DISCLOSURE A chromogenic material of normallycolorless form is disclosed, having a structural formula:

wherein one of R and R represents a chemical radical having thestructure s 7} f 4 5/ R5 or a chemical radical having the structurewherein R represents an alkyl radical having less than five carbon atomsor hydrogen radicals, Z represents nitro-, amino-, dialkylamino-, alkylradicals have less than five carbon atoms or hydrogen radicals, and Ycomprises nitro-, amino-, carboxyl, hydrogen and ester radicals and theremaining other R and R comprises amino-, nitro-, hydrogen, alkyl havingless than five carbon atoms, acetamido and halogen radicals; R compriseshydrogen radicals and alkyl radicals having less than five carbon atoms;and R comprises alkyl radicals having less than five carbon atoms-saidmaterial assuming a colored form upon reactive contact with a Lewis acidmolecule. Examples include 2-(2-carboxyanilino -6-diethylaminofiuoran;

2'-anilino-6'-diethylaminofluoran;

2'- 3-carbomethoxy-Z-naphthylamino) -6'-diethylaminofluoran;

2- (2-carbomethoxyanilino -6'-diethylamio-3 -methylfiuoran;

2- 3 -carboxy-2-naphthylamino) -6 '-diethylamino-3 methylfluoran;

6- 2-carboxyanilino -2'-chloro-6-diethylamino-3'- methylfluoran;

2'- 2-carboxy-4-nitroanilino) -6'-diethylaminoflu0ran;

6-diethy1amino-2'- (N-methylanilino) fluoran; and

6'-diethylamino-2'- (2,4-dinitroanilino) fluoran.

This is a division of application Ser. No. 90,097, filed Nov. 16, 1970,now Pat. No. 3,681,390 issued Aug. 1, 1972, which is acontinuation-in-part of abandoned application Ser. No. 792,401, filedJan. 21, 1969.

3,746,562 Patented July 17, 1973 2 BACKGROUND OF THE INVENTION Thisinvention pertains to chromogenic compounds for use in pressuresensitive record material and to an improved mark-forming manifoldsystem incorporating these chromogenic compounds. More specifically,this invention pertains to nitroand aromatic amino-substituteddialkylamino fluorans which have the form of substantially colorless,i.e., white, or slightly colored solids, or approach being colorlesswhen in liquid solution, but which may be converted to dark-coloredforms upon reactive contact with appropriate acidic material. As used inmark-forming systems, marking in desired areas on support webs or sheetsmay be accomplished by effecting localized reactive contact between thenovel chromogenic material ad the acidic material on or in such a web orsheet, such material being brought thereto by transfer, or originallythere, in situthe desired reactive contact forming dark-coloredmaterials in the intended image areas.

This invention further, and in the most preferred embodiment, relates tosuch chromogenic compounds which, when placed in reactive contact withcertain Lewis acid materials, yield neutral-colored, i.e., gray toblack, reaction products. Other chromogenic compounds of this inventionyield green, purple, gray-green or gray-purple reaction products. Suchneutral-colored (black) reaction products find particular use inpressure-sensitive, markforming recording systems by virtue of theirhaving improved stability on exposure to light and improved reproductioncapabilities when copied by xerographic or diazo processes. Thechromogenic compounds of the present invention are nitroand aromaticamino-substituted fiuorans.

Pressure-sensitive, mark-forming systems of the prior art include thatdisclosed in abandoned application for Letters Patent No. 392,404, filedAug. 27, 1964, in the names of Robert E. Miller and Paul S. Phillips,Jr. The abovementioned patent application provides a marking system ofdisposing on and/or within sheet support material, mutually reactant butunreacted mark-forming components (at least one component of which is apolymeric material) and a liquid solvent in which each of themarkforming components is solublesaid liquid solvent being present insuch form that it is maintained isolated by a pressure-rupturablebarrier from at least one of the markforming components until anapplication of pressure causes a breach or rupture of the barrier in thearea delineated by the pressure pattern. The mark-forming componentsthereby are brought into reactive contact, producing a distinctive mark.

It is an object of this invention to provide new and improved substanceshaving chromogenic properties which may be incorporated in a web orcoated onto the surface of a web to provide a manifolding unit, andwhich are, moreover, useful in carrying out improved methods of markinginvolving reactive contact with a color-activating material to yielddark-coloredreaction products in areas where marking is desired.

It is another object of this invention to provide compounds, based uponthe nitroand aromatic aminosubstituted dialkylamino fluorans disclosedherein which are substantially colorless, or slightly colored ofiering anew and improved variety of chromogenic characteristics, and yieldingdark-colored substances upon contact with color-activating materials.

It is a further object of this invention to provide new and improved,normally substantially colorless, chromogenic substances yielding Lewisacid-reacted color products which exhibit improved color stability onexposure to light and improved reproduction capabilities when copied byxerographic or diazo processes.

It is further object of this invention to provide new and improved,normally substantially colorless, chromogenic substances yieldingcolored reaction products when placed in reactive contact with certainselected Lewis acid materials.

It is a further object of this invention to provide new and improved,normally substantially colorless, chromogenic substances yieldingneutral-colored, i.e., gray to black, reaction products when placed inreactive contact with certain selected Lewis acid materials.

It is a further object of this invention to provide a new and improvedmark-forming system which comprises disposing, within a web or upon thesurface of a web or sheet-support-material, unreacted chromogenicmaterial in a location suitable for subsequent reactive contact with anacidic material to produce dark-colored reaction products, thusproviding means for making marks of desirable color intensity and hue.

In accordance with one feature of this invention, there is provided asubstantially colorless or slightly colored, chromogenic compound havingthe structural formula:

wherein one of R and R represents a chemical radical having thestructure or a chemical radical having the structure 1 8 7 s 4 itwherein R represents an alkyl radical having less than five carbon atomsor hydrogen, Z represents nitroamino-, dialkylamino-, alkyl radicalshaving less than five carbon atoms or hydrogen radicals, and Y comprisesnitro-, amino-, hydrogen, carboxyl (-COOH) and ester (-COOR radicalswherein R represents an alkyl radical having less than five carbon atomsand the remaining one of R and R comprises amino-, nitro, hydrogen,alkyl having less than five carbon atoms, acetamido and halogenradicals; R comprises hydrogen radicals and alkyl radicals having lessthan five carbon atoms; and R comprises alkyl radicals having less thanfive carbon atoms. Examples of these compounds include2-(2-carbomethoxyanilino)-6'-diethylaminofluoran having the structuralformula:

2- 3-carboxy-2-naphthylamtno) (i'-diethylaminofiuoran having thestructural formula:

0 Cal-I5 3 CrHs O \N G 2-(2carboxyanllino)-6-diethylamiuo3-methylflu0ranhaving the structural formula:

0 our; C41 O C=O III 2-anilino-6'-diethylamino-3'-methy1fluoran havingthe structural formula 2-(3carbomethoxy-2-naphthylamino)-6'-diethylamino-3'- methylfluoran havingthe structural formula:

5- (2-carboxyanalino) -2-chloro-6-diethyiamino-3-methylfluoran havingthe structurral formula:

C=O 6H 2- (Z-carb oxy-4-nitroaniltno -6-dlethylaminofluoran having thestructural formula:

6'-dlethylamino-2'-(N-methylanilino)fluoran having the structuralformula:

6'-dlethylamlno-2'-(2,4-dln1troanllino)fluoran having the structuralformula:

C=O I Other examples of these compounds that have been pre 1 paredinclude:

from reaction between preferred ones of the chromogenic materials ofthis invention and specified Lewis-acid reactive materials isimmediately aware that such reaction products are substantially neutralin hue.

BRIEF DESCRIPTION OF THE DRAWING Melting Compound Color point, C.

1 2-anilino-6-diethylaminofluoran 203-205 2--2-(2-carboxyanllino)-6-diethylaminofluora 252-253 32-anilino-6diethylamino-3-methylfiuors.n 195-122 43-diethylamino-7-(p-toluidlno)fiuoran 183-1 5-diethylarnino-7'-(N-methylanilino)fiuoran. o 162-163 63'-diethylamino-6-methyl-7(p-toluidino)flnoran Gray-green 206-208 72-anilino-fi-diethylamino-G-nitrofluoran Green 113-115 8--2-anilino-6-diethylamino-5-nitrofiuoran. 264-26t3 92"an.ilin0-6'-diethylamino-tl-amlnofiuoran 253-254 10.2-anilino6-diethylamino-fi-arninofiuoran 263-2fi5 11.3'-diethylarnino-7-(N-methylanilino)-6-n tr0fluoran 12....3-diethylamino-7-(N-methylanilino)-5-mtrofluoran. 133-dlethylamino-7-(N-methylanilino)-6-aminofluoran 14-3-diethylamino-7-(N-methylanilino)-5-arninofluoran2-anilino-6-diethylarnino-3-methyl-fi-nitrofluoran o 215-216 612-anilin0-6-d.iethylamino3-methyl-6-aminofluoran Purple-neutral 148-1501 Not determined.

In accordance with another feature of this invention, a new compositionof matter is disclosed which comprises a dark-colored product ofchemical reaction having a resonant chemical structure and produced bycontact of a color-activating material with one of the above-mentionedchromogenic compounds. The color-developing or activating material is anacidic substance useful for converting the chromogenic compounds tocolored forms.

The method of marking of this invention, i.e., the method of developinga dark-colored material from substantially colorless or slightly coloredchromogenic compounds, comprises providing a chromogenic compoundselected from among the above-mentioned compounds and bringing suchchromogenic compound into reactive contact with an acidiccolor-activating substance, in areas where marking is desired, toproduce a dark-colored form of the chromogenic compound by the actionthereon of said acidic substance.

Acidic materials employed in this invention can be any compound withinthe definition of a Lewis acid, i.e., any electron acceptor. Preferably,acidic organic polymers such as phenolic polymers are employed as theacidic material. The chromogenic materials exhibit the advantage ofimproved color stability when they are reacted with such phenolicpolymers. Solution formation of solid particles of the polymericmaterial in a solvent system with the substantially colorlesschromogenic compounds permits penetration of the dark-colored reactionproduct into a porous support sheet, e.g., paper, so that the coloredform of the chromogenic materials is absorbed into the body of the sheetand is not merely on the surface of the sheet. The absorption featureprovides protection against erasure of recorded data by attrition of thesurface of a record sheet made in accordance with the present invention.

Preferred chromogenic materials of this invention are those which yield,as the dark-colored reaction product with above-described Lewis-acids, aneutral, i.e., gray to black substance. Such preferred chromogenicmaterials are eligible to be used in the preferred pressure sensitiverecord units and mark-forming units of this invention. It is understoodthat colors with respect to hue, saturation, and lightness arecustomarily identified in a largely subjective manner. Neutral colors,i.e., shades which range from gray to black and which are substantiallylacking in hue and saturation are also customarily identified in asubjective manner. An observer of the products resulting ponent, such asan acid clay or a phenolic polymeric material lies within the lower webor undersheet or upon the upper surface of the lower web or undersheet.A colored mark is made by the use of a stylus, a type character, orother pressure-exerting means applied to the two-sheet unit manifold.

The encapsulated solution is released on the event of rupture of thecapsules in writing operations, as is shown in FIG. 2. FIG. 2 is asectioned view of the two-sheet manifold of FIG. 1. The elements are notto scale and are so-shown in order to more efiectively depict theirinterrelation. The released solution is transferred from the overlyingor base sheet to the receiving surface of the underlying sheet inconformance with the pressure pattern of the writing operation. Thedrawing shows that the top of the underlying sheet is coated orimpregnated with a material reactant with the chromogenic material,e.g., an acid clay or an acidic phenolic polymer material; and thatcapsules are present on the overlying or base-sheet which capsulescontain a liquid solution of chromogenic material. In another embodimentof the record material, however, the capsules can contain the polymericphenolic material in liquid solution and the receiving surface of theunderlying sheet can be supplied with the chromogenic material. Theimprovement in the system resides in the chromogenic materiaLwhichchromogenic material is the substance of the instant invention.

Referring again to FIG. 1, comprising an overlying or base-sheet havingthe chromogenic material located within or upon the sheet; it ispossible to incorporate the chromogenic material in a solid,crystalline, state in a binder material so that the chromogenic materialmay be transferred from the overlying sheet, upon the application ofpressure, to deposit some of the chromogenic material on the receivingsurface of the undersheet, which receiving surface carries acolor-activating polymeric material. Preferably, the chromogenicsubstance is dissolved in an appropriate solvent and minute droplets ofthe solution of the chromogenic material are encapsulated in minute,rupturable, capsules. It is apparent that many other arrangements arepossible, including different configurations and relationship of thesolvent and all of the markforming materials with respect to theirencapsulation and location on the supporting underlying or overlyingsheets or webs can be envisioned. Such arrangements are thoroughlydescribed in the aforementioned application Ser. No. 392,404 in thenames of Miller et al. and need not be repeated herein.

7. SUMMARY OF THE INVENTION It is noted that the polymeric mark-formingcomponents should have a common solubility with the chromogenic materialin at least one liquid solvent when the acid-reacting material is aphenolic or other acidic organic polymer. It is also noted that in asingle system several chromogenic materials may be used with the same ordifferent polymeric materials. Several polymeric materials can bereactively contacted with a single chromogenic compound or with amixture of chromogenic compounds.

As mentioned above, the solvent can be maintained in physical isolationin minute droplets until such time as it is released by application ofpressure. This may be accomplished by several known techniques, but,preferably, isolation is maintained by encapsulation of individualdroplets of the solvent in a microcapsule according to the proceduresdescribed, for example, in US. Pat. No. 2,712,- 507, issued July 5, 1955on the application of Barrett K. Green; 2,730,457, issued Jan. 10, 1956on the application of Barrett K. Green and Lowell Schleicher; 2,800,457,issued July 23, 1957 on the application of Barrett K. Green and LowellSchleicher; 2,800,458, issued July 23, 1957 on the application ofBarrett K. Green, reissued as Reissue Pat. No. 24,899 on Nov. 29, 1960;and 3,041,289 issued June 26, 1962 on the application of Bernard Katchenand Robert E. Miller. The microscopic capsules, when disposed within orupon a supporting web as a multiplicity in contiguous juxtaposition, arerupturable by pressure, such as normal marking pressure found, forexample, in writing or typing operations.

The material or materials chosen as the wall material for thedroplet-containing microcapsules, in addition to being pressurerupturable, must be inert or unreactive with respect to the intendedcontents of the capsules and the other mark-forming components so thatthe capsule wall material will remain intact under normal storageconditions until such time as it is released by an application ofmarking pressure. Preferred examples of eligible capsule wall materialsinclude gelatin, gum arabic and many others thoroughly described in theaforementioned patents.

For most uses in record material, the capsule size should not exceedabout 50 microns in diameter. Preferably, the capsules should be smallerthan about microns in diameter.

The acidic organic polymeric material useful for developing the color ofchromogenic compounds in this invention include phenolic polymers,phenol acetylene polymers, maleic acid-rosin resins, partially of whollyhydrolyzed styrene-maleic anhydride copolymers and ethylenemaleicanhydride copolymers, carboxy polymethylene and wholly or partiallyhydrolyzed vinylmethylethermaleic anhydride copolymer and mixturesthereof.

More specifically, phenolic polymers found useful include alkyl-phenolacetylene resins, which are soluble in common organic solvents andpossess permanent fusibility in the absence of being treated bycross-linking materials. Another specific group of useful phenolicpolymers are members of the type commonly referred to as novolacs, (atype of phenolformaldehyde polymeric material) which are characterizedby solubility in common organic solvents and which are, in the absenceof cross-linking agents, permanently fusible. Resol resins, if they arestill soluble, may be used, though they are subject to change inproperties upon aging. Generally, phenolic polymer material found usefulin practicing this invention is characterized by the presence ofhydroxyl groups and by the absence of groups such as methylol, whichtend to promote infusibility or cross-linking of the polymer, and,further, by being soluble in organic solvents and relatively insolublein aqueous media. Again, it should be remembered that mixtures of theseorganic polymers and other acidic materials can be employed.

A laboratory method useful in the selection of suitable phenolic resinsis the determination of the infrared absorption pattern. It has beenfound that phenolic resins which undergo absorption in the 3200-6500 cm?region (which is indicative of hydroxyl groups) on the resin moleculesand which do not absorb in the 1600-1700 cm.- region are eligible. Thislatter absorption region is indicative of desensitization of hydroxylgroups which desensitization renders such groups unavailable forreaction with the chromogenic materials.

The preparation of some organic polymeric materials useful forpracticing this invention has been described in Industrial andEngineering Chemistry, volume 43, pages 134 to 141, January 1951, and aparticular polymer thereof is described in Example I of US. Pat. No.2,052,093, issued to Herbert H'cinel on Aug. 25, 1936. The preparationof the phenol-acetylene polymers has been described in Industrial andEngineering Chemistry, volume 41, pages 73 to 77, January 1949. Thepreparation of maleic anhydride copolymers is described in theliterature, such as, for example, one of the maleic anhydride vinylcopolymers, as disclosed in Vinyl and Related Polymers, by Calvin E.Schildknecht, second printing, published April 1959, by John Wiley &Sons, Incorporated: see pages 65 to 68 (styrene-maleic anhydridecopolymer), 530 to 531 (ethylene-maleic anhydride copolymer), and 628 to630 (vinylmethylether-maleic anhydride copolymer).

When the acidic material used as a mark-forming component in the presentinvention is one of the aforementioned organic polymers, the liquidsolvent chosen must be capable of dissolving it. The solvent may bevolatile or nonvolatile, and a singleor multiple-component solvent maybe used which is wholly or partially volatile. Examples of volatilesolvents useful in practicing the present invention include toluene,petroleum distillate, perchloroethylene, and xylene. Examples ofnonvolatile solvents include high-boiling-point petroleum fractions andchlorinated biphenyls. Generally, the solvent chosen should be capableof dissolving at least about 0.3 percent, by Weight, of the chromogenicmaterial, and at least about 3 to 5 percent, by weight, of the acidicpolymeric material to yield an effective reaction. However, in thepreferred system, the solvent should be capable of dissolving an excessof the polymeric material, so as to provide every opportunity forutilization of the chromogenic material and, thus, to assure maximumcoloration at the reaction site.

A further criterion for selection of the solvent is that the solventmust not interfere with the mark-forming reaction. In some instances,the presence of the solvent may be found to interfere with themark-forming reaction or diminish the intensity of the mark, in whichinstances the solvent chosen should be sufiiciently volatile to assureits removal from the reaction site soon after having brought themark-forming components into reactive contact so that the mark-formingreaction can proceed.

Since the mark-forming reaction requires that an intimate mixture of thecomponents be brought about through solution of said components, one ormore of the mark-forming components can be dissolved in solvent dropletsisolated by encapsulation, the only requirement being that at least oneof the components essential to the mark-forming reaction be maintainedisolated until the mark-forming reaction is desired.

In the usual case, the mark-forming components are so chosen as toproduce a mark upon application of pressure to a coated system of sheetsat room temperature (20 to 25 degrees centigrade). However, the presentinvention also includes a system wherein the solvent component is notliquid at temperatures near room temperature but is liquid and incondition for forming solutions only at elevated temperatures.

The support sheet member on which components of the system are disposedmay comprise a single or a dual sheet assembly. In the case where allcomponents are disposed on a single sheet, the record material isreferred to as a self-contained or autogenous system. Where there mustbe a migration of solvent, with or without the mark-forming component,from one sheet to another, the record material is referred to as atransfer system. (Such a system may also be referred to as a two-foldsystem, in that at least two sheets are required and each sheet includesa component, or components, essential to the mark-forming reaction.)Where an adequate amount of the colored reaction product is produced inliquid or dissolved form on a surface of one sheet, a colored mark canbe recorded on a second sheet by transfer of the colored reactionproduct.

In a preferred case, where microcapsules are employed, they can bepresent in the sheet support material either disposed therethroughout oras a coating thereon, or both. The capsules can be applied to the sheetmaterial as a dispersion in the liquid vehicle in which they weremanufactured, or, if desired, they can be separated from the vehicle andthereafter dispersed in a solution of the acid-reacting polymericcomponent (for instance, 30 grams of water and 53 grams of a 1 percent,by weight, aqueous solution of polyvinylmethylether-maleic anhyride) toform a sheet-coating composition in which, because of the inertness ofthe solution and the capsules, both components retain their identity andphysical integrity. When this composition is disposed as a film on thesupportmaterial and dried, the capsules are held therein subject torelease of the contained liquid by rupture of the capsule walls. Thelatter technique, relying on the inertness of the microcapsule and thedispersing medium of the film-forming mark-forming polymeric component,provides a method for preparing a sensitive record material coatinghaving the capsules interspersed directly in a dry film of the polymericmaterial as the film is laid down from solution. A further alternativeis to disperse one or more markforming components, and thechromogenic-material-containing microcapsules in a liquid medium not asolvent for either the mark-forming component or the microcapsules, withthe result that all components of the mark-forming system may bedisposed on or within the support sheet in the one operation. Of course,the several components may be applied individually. The capsules canalso be coated onto a sheet as a dispersion in a solution of polymericmaterial which is not necessarily reactive with the capsulecontainedsolution of chromogenic materials.

The respective amounts of the several components can be varied accordingto the nature of the materials and the architecture of the recordmaterial unit desired or required. Suitable lower amounts include, inthe case of the chromogenic material, about 0.005 to 0.075 pound perream (a ream in this application meaning five hundred (500) sheets of25" x 38" paper, totalling 3,300 square feet); in the case of thesolvent, about 1 to 3 pounds per ream; and in the case of the polymer,about 0.5 pound per ream. In all instances, the upper liimt is primarilya matter of economic consideration.

The slurry of capsules can be applied to a Wet web of paper, forexample, as it exists on the screen of a Fourdrinier paper machine, soas to penetrate the paper web a distance depending on the freeness ofthe pulp and the water content of the web at the point of application.The capsules can be placed directly in or on a paper or support sheet.Not only capsule structures, but continuous films which contain amultitude of microscopic, unencapsulated, droplets for local release inan area subjected to pressure can be utilized. (See, for example, US.Pat. No. 2,299,694 which issued Oct. 20, 1942, on the application ofBarrett K. Green.)

With respect to the acidic organic polymeric component, a solutionthereof in an evaporable solvent can be introduced into an amount ofwater and the resulting mixture can be agitated while the evaporablesolvent is blown off by an air blast. This operation leaves an aqueouscolloidal dispersion slurry of the polymeric material, which may beapplied to finished paper so as to leave a surface residue, or theslurry may be applied to a wet web of paper or at the size-press stationof a paper making machine. In another method for making apolymer-sensitized sheet, the water-insoluble polymer can be ground to adesired or required particle size in a ball mill with water, preferablywith a dispersing agent, such as a small quantity of sodium silicate. Ifa binder material of hydrophilic properties is ground with the polymericmaterial, the binder itself may act as a dispersant. If desired, anamount of binder material of up to 40 percent, by weight, of the amountof polymeric material can be added to the ballmilled slurry ofmaterials-such binder materials being of the paper coating binder class,including, for example, gum arabic, casein, hydroxyethylcellulose, andlatexes (such as styrene-butadiene copolymer). If desired, oilabsorbents in the form of fullers earths may be combined with thepolymeric material particles to assist in retaining, in situ, the liquiddroplets of chromogenic material solution to be transferred to it indata-representing configuration, for the purpose of preventing bleedingof the print.

Another method for applying the chromogenic or polymeric materialindividually to a single sheet of paper is by immersing a sheet of paperin 1-10 percent, by weight, solution of the material in an evaporablesolvent. Of course, this operation must be conducted individually foreach reactant, because if the other reactant material were present,contact of the reactants would result in a premature coloration over thesheet area. A dried sheet with one component can then be coated with asolution of another component, the solvent of which is a nonsolvent tothe already-supplied component.

The polymeric material can also be dissolved in ink composition vehiclesto form a printing ink of colorless character and, thus, may be used tospot-print a proposed record-sheet-unit sensitized for recording, in areaction-produced color in those spot-printed areas, by application of asolution of the chromogenic material. In the case of phenolic polymer, aprinting ink may be made of up to 75 percent, by weight, of the phenolicpolymeric material in a petroleum-based solventthe ink being built to aviscosity suitable for printing purposes. The relative amounts ofreactive, mark-forming, components to be used in practice of thisinvention, are those most convenient and economical amounts consistentwith adequate, desired or required visibility of the recorded data. Theresolution of the recorded data is dependent on, among other things,particle or capsule size, distribution and amount of particles orcapsules, liquid solvent migration, chemical reaction efiiciency, andother factors, all of which can be optimized empirically by one skilledin the art. Such factors do not determine the principle of the presentinvention, which invention, in part, relates to means for enabling thebringing into solution contact, by marking pressure, two normally solid,chemically reactive, components dissolved in a common liquid solventcomponent held isolated as liquid droplets. The isolated liquid dropletsare preferably in marking pressure-rupturable capsules havingpolymeric-film walls, or are isolated, as a discontinuous phase, in acontinuous marking pressure-rupturable film.

In the color system of this invention the acidic markforming materialreacts with the chromogenic material to effect distinctive colorformation or color change. In a multi-sheet system in which an acidicorganic polymer is employed, it may be desirable to include othermaterials to supplement the polymer reactants. For example, kaolin canbe added to improve the transfer of the liquid and/or the dissolvedmaterials between the sheets. In addition, other materials such asbentonite, attapulgite, talc, feldspar, halloysite, magnesiumtrisilicate, silica gel, pyrophyllite, zinc sulfate, calcium sulfate,calcium citrate, calcium phosphate, calcium fluoride, barium sulfate andtannic acid can be included.

Various methods known to the prior art and others disclosed in theaforementioned abandoned application Ser. No. 392,404 in the names ofMiller et al. and in U.S. Pat. 3,455,721 issued July 15, 1969 on theapplication of Phillips et a1. can be employed in compositions usefulfor coating mark-forming materials into supporting sheets. An example ofthe compositions which can be coated onto the receiving surface of anunderlying sheet of a multi-sheet to react with a capsule coating on theunderside of an overlying sheet is as follows:

Coating composition: Percent by weight Phenolic polymer mixture 17 Papercoating kaolin (white) 57 Calcium carbonate 12 Styrene butadiene latex 4Ethylated starch 8 Gum arabic 2 Having disclosed, generally, thechromogenic materials of this invention and preferred methods forutilizing the novel chromogenic materials, in combination with othermaterials, as reactive components in mark-forming record material;examples will now be disclosed wherein preparation of several of thechromogenic materials is described.

EXAMPLE 1 Preparation of 2-(2-carboxyanilino)-6'-diethyl aminofluoran2'-amino-6diethylaminofiuoran, a starting material in the reaction ofthis example, is prepared as follows: 2.2 parts, by weight of2-carboxy-4'-diethylamino-2'-hydroxybenzophenone, 1 part, by weight, ofp-nitrophenol, and 40 parts, by weight, of 90 percent, by weight,sulfuric acid are heated together for about one hour at 150 degreescentigrade. The mixture is then poured onto about 225 parts, by weight,of ice and made alkaline to a pH of about 8 by addition of diluteammonium hydroxide. The alkaline system is extracted by benzene and thebenzene is washed with 10 percent, by weight, aqueous sodium hydroxidesolution and then water. The washed benzene extract is then evaporatedto dryness and the residue is chromatographically purified over aluminaand then recrystallized from benzene-petroleum ether. The purifiedproduct is reduced with stannous chloride solution to yield2'-amino-6-diethylaminofiuoran, having a melting point of about 214degrees centigrade.

To obtain the title compound of this example: 7.8 grams of theabove-prepared 2-amino-6'-diethylaminofiuoran, 4.0 grams ofo-bromobenzoic acid, 2.8 grams of potassium carbonate, 0.1 gram ofcopper powder, and 50 milliliters of n-amyl alcohol were refluxed forabout 3 hours. The reaction mixture was cooled and low-boilingpointpetroleum ether was added to cause separation of the crude reactionproduct. 4.6 grams of a black solid was recovered and waschromatographicaly purified over silicon dioxide and then precipitatedfrom a 5 percent, by weight, aqueous solution of sodium bicarbonateusing dilute hydrochloric acid. A benzene solution of the purifiedproduct imparted a black color to paper coated with a mixture of kaolinand phenolic polymer.

EXAMPLE 2 Preparation of 2'-(2-carbomethoxyanilino)-6'-ethylan1inofluoran 1.0 gram of the crude reaction product prepared inExample 1, above, was refluxed for about 15 minutes with 0.3 gram ofdimethyl sulfate, 0.5 gram of dicyclohexylamine, and 15 milliliters ofacetone to methylate the crude product. Solvent was then evaporated fromthe system until the system became syrupy and then the system was heatedover a steam bath for an additional 15 minutes. The system was extractedwith 50 milliliters of benzene and the benzene solution was run throughan activated alumina chromatograph column using a solution ofbenzene-diethyl ether-ethyl acetate (222:1, by volume, respectively) aseluant. The eluate was concentrated by evaporation and then, tocrystallize the reaction product, low-boiling-point petroleum ether wasadded. The reaction product exhibited a melting point of 169170 degreescentigrade. A benzene solution of the reaction product imparted a blackcolor to paper coated with a mixture of kaolin and phenolic polymer.

EXAMPLE 3 Preparation of 2'-anilino-6-diethylaminofluoran One gram ofthe crude reaction product prepared in Example 1, above, was heated to250-260 degrees centigrade for about one hour to decarboxylate the crudeproduct. It was then dissolved in 150 milliliters of benzene and thesolution was washed with 2-50 milliliter portions of 1 percent, byweight, aqueous sodium carbonate solution followed by a wash with water.The washed benzene solution was concentrated to about 50 milliliters byevaporation and the reaction product was precipitated using petroleumether. The product was chromatographically purified over activatedalumina and recrystallized from benzene-petroleum ether. The purifiedreaction product exhibited a melting point of 196-197 degrees centigradeand a benzene solution of its imparted a green color to paper coatedwith a mixture of kaolin and phenolic polymer.

EXAMPLE 4 Preparation of 2'-(3-carboxy-2-naphthylamino)-6'-diethylaminofluoran 0.2 gram of 2-amino-6'-diethylaminofluoran, thestarting fluoran material of Example 1 above, was refluxed for about 30minutes with 0.13 gram 2-bromo-3-naphthoic acid, 0.08 gram of potassiumcarbonate, 10 milligrams of copper powder, and 5 milliliters of n-amylalcohol. The system was then shaken with a mixture of 50 milliliters ofwater and milliliters of benzene. The aqueous layer was washed withbenzene and was acidified to a pH of about 3. The precipitate whichformed on acidification was extracted with milliliters of benzene andthe desired compound was isolated from the benzene by evaporation. Abenzene solution of the product imparted a green color to paper coatedwith a mixture of kaolin and phenolic polymer.

EXAMPLE 5 Preparation of 2'-(3-carbomethoxy-2-naphthylamino)-6'-diethylaminofiuoran Material from the product of Example 4, above,was methylated according to the procedure described in Example 2, above.A benzene solution of the resulting product imparted a green color topaper coated with a mixture of kaolin and phenolic polymer.

EXAMPLE 6 Preparation of 2'-(2-carboxyanilino)-6-diethy1amino-3-methylfluoran The reaction of this example wasconducted according to the same procedure as that described in Example1, above, and also using the same materials, in like amounts, asdescribed in Example 1, above, with the exception that3-methyl-4-nitrophenol was substituted for p-nitrophenol in preparationof the fluoran starting material. The fluoran starting material of thisexample is 2-amino-6'-diethylamino-3'-methylfluoran.

Purification of the title material of this example was conducted bysuspending the crude product in a dilute, aqueous, potassium carbonatesolution, washing the solution with benzene, acidifying the washedsolution to about pH 4 and extracting the precipitate which therebyformed with benzene. The product exhibited a melting point of 253-255degrees centigrade. A benzene solution of the product imparted a purplecolor to paper coated with a mixture of kaolin and phenolic polymer.

EXAMPLE 7 Preparation of 2'-(Z-carbomethoxyanilino)-6-diethylamino-3'-methylfluoran A portion of the product prepared inExample 6, above, was methylated according to the procedure of Example2, above. A benzene solution of the product imparted a purple color topaper coated with a mixture of kaolin and phenolic polymer.

EXAMPLE 8 Preparation of 2'-anilino-6'-diethylamino-3-methylfiuoran Aportion of the product prepared in Example 6, above, was decarboxylatedaccording to the procedure of Example 3, above. The product exhibited amelting point of 195-198 degrees centigrade. A benzene solution of theproduct imparted a black color to paper coated with a mixture of kaolinand phenolic polymer.

EXAMPLE 9 Preparation of 2-(3-carboxy-2-naphthylamino)-6-diethylamino-3-methylfluoran EXAMPLE 10 Preparation of2'-(3-carbomethoxy-Z-naphthylamino)- 6-diethylamino-3'-methylfiuoranMaterial from the product of Example 9, above, was methylated accordingto the procedure described in Example 2, above. A benzene solution ofthe resulting product imparted a dark grayish-green color to papercoated with a mixture of kaolin and phenolic polymer.

EXAMPLE 11 Preparation of (and 6)-(2-carboxyanilino)-2-chloro-6-diethylamino-3-methylfiuoran 5 (and 6)-amino-2-chloro-6'-diethylamino-3-methylfluoran, a starting material inthe reaction of this example, is prepared as follows: 5 grams ofm-diethylaminophenol, 5.8 grams of 4-nitrophthalic anhydride and 100milliliters of benzene are refluxed together for about three hours. Thereaction mixture is extracted by sodium carbonate solution and theextract is acidified. The precipitate which is thus thrown down betweenpH 6 and 2 is collected and is heated with 3-methyl-4-chlorophenol in 80percent, by weight, sulfuric acid for about 3 hours at 95-105 degreescentigrade. The resulting reaction product is reduced with stannouschloride solution and is extracted with benzene.

To obtain the title compounds of this example: 0.43 gram of theabove-prepared 5 (and 6)-amino-2'-chloro-6-diethylamino-3-methylfluoran, 0.2 gram of o-bromobenzoic acid, 0.14gram of potassium carbonate, milligrams of copper powder, and 5milliliters of n-amyl alcohol were refluxed for about 3 hours. Theproduct of the reaction was isolated and purified by the procedurediscussed in Example 1, above. A benzene solution of the purifiedproduct imparted a red color to paper coated with a mixture of kaolinand phenolic polymer.

EXAMPLE 12 One gram of 2-carboxy-4-diethylamino-Z-hydroxybenzophenonewas dissolved in a mixture of 4 ml. of concen- 14 trated sulfuric acidand an equal volume of fuming sulfuric acid at a SO content of 20% underexternal cooling to about 15 C. with mechanical stirring. To thesolution were added 1.9 grams of 4-anilino-3-methylphenol in smallportions, and stiring was continued for 16 hours at about 20 C. Thereaction mixture was poured into 200 grams of ice-Water, basified with10% aqueous NaOH, and extracted with benzene. The benzene solution waswashed with 10% aqueous NaOH, 2% aqueous NaCl, and finally with water.After concentrating to about 40 ml., it was chromatographed on activatedalumina. Eluting with benzene removed an orange dye from the column. Thedesired product, 2-anilino-6'-diethylamino-3'-methylfluoran, was eluted3:321 mixture of benzene-ether-ethyl acetate, exhibiting a weight of1.17 grams melting point 194-196. The yield was calculated to be 77percent of theory.

What is claimed is:

1. A pressure sensitive record unit comprising:

(a) support web or sheet material,

(b) mark-forming components and a releasable liquid solvent for saidmark-forming components arranged in contiguous juxtaposition andsupported by said sheet material,

(c) said mark-forming components comprising at least one chromogenicmaterial of the structure:

wherein:

one of R and R represents a chemical radical selected from the groupconsisting of wherein R represents a chemical radical selected from thegroup consisting of an alkyl radical having less than five carbon atomsand hydrogen, Z represents a chemical radical selected from the groupconsisting of nitro-, amino-, alkyl radicals having less than fivecarbon atoms and hydrogen, and Y represents a chemical radical selectedfrom the group consisting of nitro-, amino-, hydrogen, carboxyl (-COOH),and ester (COOR wherein R represents an alkyl chemical radical havingless than five carbon atoms; the remaining one of R and R represents achemical radical selected from the group consisting of amino-, nitro-,chlorine, alkyl having less than five carbon atoms, acetam-ido andhydrogen; R represents a chemical radical selected from the groupconsisting of hydrogen and alkyl radicals having less than five carbonatoms; and R represents alkyl radicals having less than five carbonatoms; and an electron-accepting material of the Lewis acid typereactive with said chromogenic material to produce a mark; whichcomponents upon pressure-release of the liquid solvent are brought intoreactive contact in the released solvent.

2. The record unit of claim 1 wherein at least one of the mark-formingcomponents is maintained in isolation from the other mark-formingcomponents prior to the release of the solvent.

3. The record unit of claim 1 wherein the liquid solvent is present asthe nucleus of a microcapsule.

4. The record unit of claim 1 wherein the chromogenic material isdissolved in the liquid solvent prior to pressure release.

5. The record unit of claim 1 wherein the mark-forming components andthe liquid solvent are present in a single support sheet.

6. The record unit of claim 1 wherein at least one member selected fromthe group consisting of the markforming components and the liquidsolvent is present in a support sheet other than the support sheethaving the remaining members of the group.

7. The record unit of claim 1 where the electron-accepting material ofthe Lewis acid type comprises a clay.

8. The record unit of claim 1 where the electron-accepting material ofthe Lewis acid type comprises at least one organic polymer.

9. The record unit of claim 8 wherein the organic polymer is a phenolicpolymer.

10. The record unit of claim 9 wherein the mark produced by reactivecontact between the phenolic polymer and the chromogenic material isneutral in color and wherein the chromogenic material is at least onematerial selected from the group of materials consisting of 2'-(2-carbomethoxyanilino -6'-diethylaminofiuoran; 2'-3-carboxy-Z-naphthylamino)-6-diethylaminofluoran; and 2'-anilino-6'-diethylamino-3-methylfluoron.

11. A mark-forming unit, comprising: a first web or sheet having on onesurface a transfer coating which contains as a finely dispersed phase aplurality of minute, pressure-rupturable capsules containing as an innerphase a solvent vehicle; a second web or sheet having an adherentcoating upon its surface or dispersed within said web or sheet, saidfirst and second webs or sheets being maintained disposed together inface-to-face relationship with said respective transfer and adherentcoatings in contiguity with each other; a first coating constituent inthe form of a substantially colorless or slightly colored chromogenicmaterial which includes as a major functional arrangement the molecularstructure wherein:

one of R and R represents a chemical radical selected from the groupconsisting of and wherein R represents a chemical radical selected fromthe group consisting of an alkyl radical having less than five carbonatoms and hydrogen, Z represents a chemical radical selected from thegroup consisting of nitro-, amino-, alkyl radicals having less than fivecarbon atoms, and hydrogen, and Y represents a chemical radical selectedfrom the group consisting of nitro-, amino-, hydrogen, carboxyl (COOH),and ester (COOR wherein R represents an alkyl chemical radical havingless than five carbon atoms;

the remaining one of R and R represents a chemical radical selected fromthe group consisting of amino-, nitro-, chlorine, alkyl having less thanfive carbon atoms, acetamido and hydrogen;

R represents a chemical radical selected from the group consisting ofhydogen and alkyl radicals having less than five carbon atoms; and

R represents alkyl radicals having less than five carbon atoms;

and a second constituent in the form of an electron-accepting materialof the Lewis acid type; one of said constituents being dissolved in saidsolvent liquid vehicle present as the inner phase of the plurality ofminute pressure-rupturable capsules in the transfer coating on or withinsaid first web or sheet, and the other of said coating constituentsbeing bonded to said second web in said adherent coating thereon butbeing accessible to other materials coming into contact with portions ofthe adherent coating, whereby, upon local impact and rupture of saidcapsules, releasing said liquid vehicle containing one coatingconstituent from at least some of the capsules onto said contiguousadherent coating, reactive contact is effected between said twoconstituents to produce a darkcolored material by the action of saidelectron-accepting material of the Lewis acid type upon said chromogenicmaterial to effect color change in said chromogenic compound to saiddark-colored material.

12. The mark-forming unit of claim 11 in which the electron-acceptingmaterial of the Lewis acid type comprises a clay.

13. The mark-forming unit of claim 11 in which the electron-acceptingmaterial of the Lewis acid type comprises an organic polymer.

14. The mark-forming unit of claim 11 in which the organic polymer is aphenolic polymer.

15. The mark-forming unit of claim 14 wherein the mark produced byreactive contact between the phenolic polymer and the chromogenicmaterial is neutral in color and wherein the chromogenic material is atleast one material selected from the group of materials consisting of 2(2-carbomethoxyanilino -6'-diethylaminofiuoran; 2'-3-carboxy-2-naphthylamino)-6-diethylaminofluoran; and2-anilino-6'-diethylamino-3'-methylfluoran.

References Cited UNITED STATES PATENTS 3,501,331 3/1970 Kimura et al1l7--36.2

MURRAY KATZ, Primary Examiner US. Cl. X.R.

